Interannual variability of precipitable water vapour—ENSO/LNSO signal

Abstract

Knowledge of the quantity of precipitable water vapour content (PWVC) in space and time over a region is of fundamental importance in hydro-meteorological studies. In the present investigation using the radiosonde data for a 17-year period from 1984 to 2000, the mean monthly precipitable water for Visakhapatnam (lat. 17°43<i>'</i>N, long. 83° 14<i>'</i>E) is evaluated

for the layers surface to be 500 mbar. The inter-annual and intra-seasonal variation of precipitable water vapour and its relation to the mean monthly rainfall have been discussed. Seasonal cycles of precipitable water during ENSO (<i>El Nino</i> Southern Oscillation) and LNSO (<i>La </i><i>Nina Southern Oscillation</i>) periods along with normal are reported. The paper also

deals with cycling rates of moisture flux and percentage occurrence of rainfall from the corresponding amount of precipitable water vapour content.